Abstract: This paper conducted a theoretical analysis of the impact of agglomeration of productive services (APS) on urban haze pollution, focusing on the role of green innovation in this process. Using a panel data set of 278 prefecture-level and above cities in China from 2005 to 2019, we empirically examined the direct effect and heterogeneity of APS on haze pollution, as well as the transmission role and threshold effect played by green innovation. Our findings were as follows: (1) the diversified agglomeration of productive services (DAPS) had a significant pro-reduction effect on haze pollution, while specialized agglomeration of productive services (SAPS) had an inverted U-shaped relationship with haze pollution. (2) Heterogeneity analyses showed that DAPS had a significant suppressive effect on haze pollution in western cities, large cities of type II, small and medium-sized cities and non-resource-based cities, and an inverted U-shaped effect on haze pollution in east-central cities, while a U-shaped effect on haze pollution in northeastern cities. SAPS exacerbated haze pollution in western cities. The impact on haze pollution in northeastern cities, resource-based cities and small and medium-sized cities was consistent with the conclusion of the full sample. The degree of agglomeration had not yet crossed the inflection point and was still at the stage of exacerbating haze pollution. (3) Green innovation was an important mechanism via which APS affected urban haze pollution, which played both a transmission effect and a threshold effect in the process.